Machines having rotating components can wear down over time due to prolonged use, even if the machines are maintained and/or periodically repaired. Some machines are not monitored for wear during use, but only are examined for wear between periods of use. For example, turbochargers in some vehicles, such as locomotives, may not have instrumentation to monitor vibration, temperatures of bearings, or rotor response during operation of the turbocharger. Excessive wear of bearings can lead to rotor instability, high displacement and eventual rubs, which can result in failure of the turbocharger. High imbalance caused by foreign object damage (FOD) or excessive deposition on the turbine blades can also lead to high shaft motion, bearing wear and eventual failure due to rotating contact with stationary parts.
Some machines include external accelerometers and/or use direct measurement of bearing temperatures to monitor bearing health. But, these devices add to the cost and complexity of the machines. Other machines can be inspected at specified megawatt intervals, but this can involve the tear down of the machine, which reduces the time that the machine can be used.